Power responsive device



Sept. 29, 1942. w. ANGsT 2,297,644

n POWER RESPONSIVE DEVICE Filed NOV. 22, 1940 FIGZ 4.3

INVENTOR WALTER ANGST BYS f l Q n is! s' v ,MATVTORNEY Patented Sept. 29, 1942 rowER RESPONSIVE DEVICE i Walter Angst, Manhasset, N. Y., assignor `to Square D Company, Detroit, Mich., a. corporation of Michigan Application November 22, 1940, Serial No. 366,676

2 Claims.

This invention relates to power responsive devices for engines, more particularly internal combustion engines such as are used 'on aircraft.

- It is an object of this invention. to provide an improved device which will respond to, or indicate, the actual power output of the engine irrespective of changes in conditions or factors under which the engine m`ay operate. Such factors may be quantity of fuel, temperature and pressure of the combustion air, or moisture and oxygen content of the same.

'Ihe invention thus aims at providing a reliable device for indicating or controlling the true power output of an engine. This object is of particular importance in the operation of long range aircraft where fuel economy and maintenance of a predetermined power output at which the engine operates most eiliciently is essential.

It is a further object of this invention toy provide a power responsive device utilizing two impulses derivable from the engine, a rst impulse proportional to the speed of the engine, the second impulse proportional to the engine torque. Both impulses are .utilized for jointly operating a movable member which may either be a pointer or, equally, a movable member of a control relay. More particularly this invention aims at providing an electrically operated power responsive instrument including means for generating measurable electric impulses, the magnitude of which is proportional .to the engine speed and including further means for varying the magnitude of such electrical impulses in response to the engine torque. Inthis manner a joint operation of a movable member,` such as a pointer,

is accomplished in dependence on engine speed and torque.

It is a further object of this invention to provide a power responsive instrument adapted for use in connection with an engine having means operable in response to the engine torque.

More particularly, this invention aims at providing a power meter suited for use with aircraft engines having pressure fluid operated means for measuring the torque of the engine, more specifically for engines having a planetary gear for driving the propeller including rotating driving and driven gears and a relatively stationary sun gear, the reaction torque on which is determinable by pressure fluid operated means.

The invention thus aims at providing a power responsive device utilizing asone of its operating impulses a pressure impulse produced by a pressure fluid operated device of the character mentioned.

The invention further aims at providing a power responsive device, simple of construction, easy to manufacture and reliable in operation requiring no further compensating lmeans for changes in operating conditions of the engine such as the aforementioned changes in atmospheric temperature, pressure, humidity, oxygen content andthe like.

Further aims, objects and advantages of this invention will appear from a consideration of the description which follows with accompanying drawing showing for purely illustrative purposes an embodiment of this invention. It is to be understood, however, that` the description is not to be taken ln a limiting sense, the scope of this invention being defined in the appended claims.

Referring to the drawing:

Fig. 1 is an illustration, partly in perspective view, of an embodiment of this invention; and

Fig. l, a section being taken on line 2--2.

A purpose of this invention is to actuate the movable member suchas the actuating arm of a relay .or an indicator in response to changes in the power output of an engine.

In Fig. 1 the movable member is shown by way of illustration in the form of a pointer I0 movable relatively to a graduated dial II and forming part of an electric meter I2 which may in principle be of the bulb or ammeter type.

' For the purpose of this description, the engine may be assumed to be an internal combustion engine of the type used on aircraft.

Two impulses are derived from the engine for actuating the aforementioned movable member or pointer in response to the engine power.

1n the .illustrated embodiment a first impulse proportional to the speed of the engine is created by an electric impulse transmitter which may be in the form of a single phase A. C. generator I3 having output terminals I4 and I5.'V

According to the present invention, the magnitude of the transmitter output is modified in response to the engine torque by output modifying means of any suitable form. This may be accomplished by providing an adjustable potentiometer which may be in the form of a variable impedance I6 connected to the transmitter by means of leads II and I8. The output terminals of the output modifying means are connected to the electric meter I2 by means of leads I9 and 20.

If the meter is of a type sensitive to changes in frequency,l for example' by reason of an inductance forming part of the meter, a network 2| of conventional structure may be connected Fig. 2 is va side view of an element shown` in 4same.

in the meter circuit to counteract changes in the indication of the meter caused by changes in frequency which normally occur at an increase in driving speed of the transmitter I3.

The output modifying means, in the illustrated embodiment the potentiometer I6, is adjusted in response to engine torque.

The device for deriving a torque impulse may be of any suitable form and is shown in the illustrated embodiment as being of the pressure fluid type responsive to the reaction exerted by the engine on its support.

In Figs. 1 and 2 the end of the engine crankshaft 22 is shown as mounted in motor casing or support 23 by means of a bearing 24. The engine crankshaft drives a propeller shaft 25 mounted in bearings 26 and 2l through a reduction gear.

The reduction gear comprises a driving gear 28 keyed to the crankshaft at 2Q, a set of planetary gears, two of which are shown at 30 and 3|, and a relatively stationary sun gear 32. The planetary gears 30 and 3i are mounted on arms 33 and 34 or" the propeller shaft 25 to drive the The driving gear 28 may be supported in the engine easing 26 by means of a further ,-1 @bearing 35.

The relatively stationary sun gear 32 may be mounted cn the propeller shaft by means of a bearing 35 and provided with two arms or lugs 3l and 38 for bracing the sun gear against rotation relatively to-the engine casing.

In operation the driving gear 28 causes the planetary gears to revolve about the sun gear, thereby exerting a reaction torque on the sun gear which is proportional tothe engine torque. From this reaction torque a pressure impulse may be derived by any suitable means, one convenient form being shown in Fig. l.

The pressure uid operated device of the illustrated embodiment comprises two pistons 39 and 40 connected to the arms 3l and 38 by means of piston rods 4I and 52. The pistons are movable in cylinders 43 and 4B mounted on, or forming part of, the housing 23. The spaces in the cylinders above the pitsons are connected by a duct d5.

Pressure fluid from a suitable source (not shown) is supplied to the device through a supply duct 46 terminating at an intake' port itl. The intake port is controlled in response to movements of the pistons relatively to the cylinders. In the illustrated embodiment, a sleeve valve is shown comprising a valve member A3 connected to, or forming part of, the piston 39. The sleeve valve has a control edge 49 cooperating with the intake portA'I. The space above the control valve may be vented through a suitable vent hole 59.

The pressure fluid operated torque device operates as follows:

Reaction on the sun gear in the direction of the arrow 3 in Fig. 1 causes the piston 39 to move into the cylinder, thereby opening the intake port 4I to admit pressure fluid into the cylinder. The entering pressure fluid forces the piston in the opposite direction until the supply of pressure fluid is shut off. The pressure exist-ing within the cylinder 43 is communicated to the cylinderv 44 through the duct 45 and is proportional to the reaction on the sun gear and, accordingly,

. the torque of the engine.

The pressure impulse is transmitted to a pressure responsive device of suitable form through a duct 5I for modifying the action of the speed impulse on the movable member or indicator of the power responsive device.

A rotary motion proportional to the speed of the engine may also be derived at the device of Fig. 2, there being-shown a helical gear train for driving a flexible shaft. A first helical gear 52 is cut into or mounted on the crankshaft meshing with a second gear 53 mounted on a shaft 55 journaled in a bracket 54. The shaft 55 terminates at 56 in a suitable shaft coupling to which a flexible shaft 5l may be connected for actuating the shaft 58 of the transmitter I3.

Returning now to the second or torque impulse,

there is shown in the illustrated embodiment a.

Bourdon tube 59 connected to the pressure duct 5I. 'I'he movable end of the Bourdon tube has linked thereto at 6I! the mechanism 6I of the potentiometer.

An expansion of the Bourdon tube in the direction of the arrow 4 in response to an increase in uid pressure representing an increase in engine torque will cause an increase in the output modifying means to which the meter I 2 responds with anrincrease in deflection of the-pointer i0.

vThe operation of the power meter shown in Figs. l and 2 is as follows:

The output of the transmitter I3 is the greater the greater the engine speed. Assuming the adjusting position of the output modifying means to be fixed, the pointer it will respond to an increase in engine speed by an increase in the deection of the pointer.

The deflection of the pointer, is further increased or decreased depending on the engine torque in response to which the output modifying means is adjusted. The pointer is thus jointly operated by the torque and speed responsive means causing a total deection of the pointer which becomes a measure of the engine power. The dial ii may, accordingly, be graduated in horsepower units.

The indication is at all times a correct measure of the engine power and is evidently not affected by such operating conditions of the engine as quality of fuel, moisture or oxygen content of the combustion air, changes in pressure, timing of ignition, etc.

Obviously the present invention is not limited to the particular embodiments herein shown and described. Other forms of electrical devices for deriving or creating impulses proportional to engine speed and torque may be used. Moreover, it is not indispensable that all the features of this invention be used conjointly since they may advantageously be employed in various combinations and sub-combinations.

What is claimed is:

l. A power meter for internal combustion engines having a planetary gear including a rotatable driving, a` rotatable driven, and a substantially stationary sun gear, said meter comprising, in combination, pressure fluid operated means for producing a iiuid pressure which is a function of the reaction torque exterted on said sun gear; an alternating current generator driven by said engine for generating an alternating electromotive force, which is a function of the speed of the engine; a variable impedance connected parallel to said generator; an indicator responsive to changes in potential, said indicator being graduated in units of horepower; and means responsive to said fluid pressure for connecting said indicator parallel to a greater or lesser portion of said impedance in dependence on said pressure, wheregine speed, an impedance connectedy across'the output f said generatonla slider on said impedance, a i-voltmeter graduated in terms of power, the terminals of said' voltmeter being connected respectivelyto one end of said impedanceV Yand to said slider, and'gear means connecting said slider and said fluid pressure operated means,.;

whereby the potential applied to said voltmeter varies directly with the power delivered by said l0 engine.

WALTER ANGsVT. 

